| Popular presumptive tests for blood include: Luminol, tetramethylbenzidine (TMB), leucomalachite green (LMG), phenolphthalein, and Hemastix® [3]. These presumptive tests have been reviewed with respect to their sensitivity, specificity, and DNA degradation. In this study, the aforementioned presumptive tests were subjected to bloodstains deposited on cotton contaminated with all-purpose bleach and compared with Raman spectroscopy as an application of a confirmatory blood test. Samples were tested for interference with the all-purpose bleach to determine the selectivity of the presumptive tests. Tetramethylbenzidine, leucomalachite green, and phenolphthalein all yielded inconclusive results when applied to a contaminated sample. Luminol and Hemastix ® yielded a positive result when tested on the all-purpose bleach, which in turn would be a false positive result. Raman spectroscopy, however, had minimal interference from the cotton substrate and/or bleach. Therefore, the potential exists for Raman spectroscopy to be implemented as a confirmatory test for blood in the presence of all-purpose bleach as an example of a contamination [4]. |
